Anatomy of Heart

Conduction system of the Heart consists of three major parts. : Sinoatowal (SA) node (2 AV Junction area 3 The bundle luanches and terminal purkinje fibres SINOATRIAL (SA) NODE > SA node is spindle shaped > 10-12 mm long > Imm thick situated in the dink - epicardium at the lateral junction of the supuvai and right atonium mena cama > Blood supply to the SA node is by the sinus modal artery. > Histologically (microscope), the dinus mode has: • Pull • Pransitional cels • Atonal muscle cells Average heart rate : 60-100 bpm] Pillls (pale Inodal cells) >P cells are onoid, small 15-10Nm in greatest diameter) and resemble. the primiting myocardial ully. Transitional cells (T cells) > Intermedialt hiturcen P cells and aterial imyocardial Internal Atrial Nyprandium (electro physiologtial properties) Antupor intermodal tract Mpadle intemodal tract VOV VA JAVA posterior internadal tract. Anterior intermodal tract (Bachmann - James) > It leaves the antero-superior part of the VA SA node ond ensues avened in front of the superior Mena coma. Meddle mtermodal Prost I Wenckelback) > 14 leaves the poster - Inferior margin of the SA node Curues behind the SVC as course along the interartial Seption to enter the superior unangin of the AV node. The posterior internadal Tract (Thoral) 7 It leaves the postero - inferder mengin of the SA mode en follows the course of wista terminale y enstachucan ridge to enter the posterior imagin of the AV node. ATRIO VENTRICULAR JUNCTIONAL AREA > It consists of three distinct zones: (1) Transitional cell zone (1) AV node ( His bundle Tromsitional cell zone 7 It is the outer layer of the AV node uwhich connects the right atalal mysendemn with on Av mode AV wode > small onoid stondime I smaller trans SA node) measuring 1x 3x5mm. > lies just beneath the right atrial epiccardius, ambi to the ostium of cornery sinus and directly alone tho inxition of the deptal leaflet of toricuspid malne > The compart AV node lucomies continous with the lundle of His and passes throught the membranous aventricular deptum. > The blood supply is through the AV nodal artery. (which is a luanch of RCA in 85-90%. and LCx im 10-15%) > Histologreally is abstration mapsthenow Pall • Transitional cells 9 Atrial myocardiel pinkinje cells > Alectrophysiologically, •AN regions •N region The Bundle of His (AV Bundle, commen Bundle) > It is a chord like distal continuation of the AV node measuring diametr 20 mm in length and up to 2mm in yu amatomically subdivided into > it is am thee portions • Prontinal mon- pentrating • Middle penetrating awal thin inh nh • Distal branching partionsnambwe names one mith • peinctarting portion is distal to AV v > porommal mon - penetraling portion hortion > middle penetrating portion will be present the membranous septins. Distal bronching portion His hundle lifurcalis at the west of the muscular deplins into eight and left bundle, immedrally distel to me membremous mentortcular septumpasstille THE BUNDLE BRANCHES AND TERMINAL PURKINJE FIBRES > The left Bundle Branch (LAB) it forms a cascade elove the left ventabulas septal surfare beneath the arta > The left bundle mith dus significant divisions. thin Ansterosuperior and thick posteroinferior fasibeles. one doss > The Right Boundle Brouck (RBB) It is the direct continuation of the this luidle positioned along the right aide of the mentricular deptiom > The right lundle branch becomes a subendocardiul structure in the middle lower thirds of the mentitul deptus and remains unbranched to the apen of the right mentielle. Stamilures Arteriers LBB (beft lumelle brach i Anterosupeños fascicle moth LAD W RCA 50%. by septal branch of LAD & AV nodal luanch of RCA, ii Posteroinfeñor fascicle 50%. only by septal brank of LAD 50% only by Av modal branch of RCA 50%. lby both Av nodal luanch of RCA by septal bramh of LAD RBB (Right handle Pormer) Similar to that of anterosupeing farticle of LBB ~ Blood Supply of the bundle branchy Note:- SV.L > Supuva Vena Cave IVE > Irfeva Vera Cane The Terminal purkinje febres > These fiberes connect with the ende of the bundle bramb to form entenneming of listh ventricly networks on the endocardial surfa > punicinje filues tend to be concentrated at tips of the papillary muscles rather than at the ease of ventricle